随机点名.

<!DOCTYPE html>
<html lang="en">

    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
    </head>
    <style>
        div {
            height: 200px;
            width: 500px;
            background-color: black;
            margin: 50px auto;
            color: aliceblue;
        }

        button {
            background-color: aquamarine;

        }

        p {
            height: 100px;
            width: 300px;
            background-color: skyblue;
            margin: auto;
            margin-top: 25px;
            text-align: center;
            line-height: 100px;
            font-size: 20px;

        }
    </style>

    <body>
        <div>
            <button>开始</button>
            <button>停止</button>
            <p></p>
        </div>
        <script>
            var arr = ['上三', '钢弹', '狗子', '老六', '小气', '王五'];
            var btn1 = document.querySelectorAll('button')[0];
            var btn2 = document.querySelectorAll('button')[1];
            var p = document.querySelector('p');
            // 点击开始
            btn1.addEventListener('click', function () {
                // 每5秒在数组内随机选择
                var time = setInterval(fn, 50);
                // fn函数
                function fn() {
                    var random = Math.round(Math.random() * (arr.length - 1) + 0);
                    p.innerHTML = arr[random];
                }
                btn2.addEventListener('click', function () {
                    clearInterval(time);
                })
            })

        </script>
    </body>

</html>